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Saturday, 11 August 2018

This
paper deals with the design and performance analysis of a three-phase single
stage solar photovoltaic integrated unified power quality conditioner
(PV-UPQC). The PV-UPQC consists of a shunt and series connected voltage compensators
connected back to back with common DC-link.The shunt compensator performs the
dual function of extracting power from PV array apart from compensating for
load current harmonics. An improved synchronous reference frame control based
on moving average filter is used for extraction of load active current
component for improved performance of the PVUPQC. The series compensator
compensates for the grid side power quality problems such as grid voltage
sags/swells. The compensator injects voltage in-phase/out of phase with point
of common coupling (PCC) voltage during sag and swell conditions respectively.
The proposed system combines both the benefits of clean energy generation along
with improving power quality. The steady state and dynamic performance of the
system are evaluated by simulating in Matlab-Simulink under a nonlinear load.
The system performance is then verified using a scaled down laboratory
prototype under a number of disturbances such as load unbalancing, PCC voltage
sags/swells and irradiation variation.

KEYWORDS:

1.Power
Quality

2.Shunt
compensator

3.Series compensator

4.UPQC

5.Solar PV

6.MPPT

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.
1. System Configuration PV-UPQC

EXPECTED SIMULATION RESULTS:

Fig.
2. Performance of PV-UPQC under Voltage Sag and Swell Conditions

Fig.
3. Performance PV-UPQC during Load Unbalance Condition

Fig.
4. Performance PV-UPQC at Varying Irradiation Condition

Fig.
5. Load Current Harmonic Spectrum and THD

Fig.
6. Grid Current Harmonic Spectrum and THD

CONCLUSION:

The
design and dynamic performance of three-phase PVUPQC have been analyzed under
conditions of variable irradiation and grid voltage sags/swells. The
performance of the system has been validated through experimentation on scaled
down laboratory prototype. It is observed that PVUPQC mitigates the harmonics
caused by nonlinear load and maintains the THD of grid current under limits of
IEEE-519 standard. The system is found to be stable under variation of irradiation,
voltage sags/swell and load unbalance. The performance of d-q control
particularly in load unbalanced condition has been improved through the use of
moving average filter. It can be seen that PV-UPQC is a good solution for
modern distribution system by integrating distributed generation with power
quality improvement.

In this paper, the design and performance of a
three phase solar PV (photovoltaic) integrated UPQC (PV-UPQC) are presented. The
proposed system combines both the benefits of distributed generation and active
power filtering. The shunt compensator of the PV-UPQC compensates for the load
current harmonics and reactive power. The shunt compensator is also extracting
maximum power from solar PV array by operating it at its maximum power point
(MPP). The series compensator compensates for the grid side power quality
problems such as grid voltage sags/swells by injecting appropriate voltage in
phase with the grid voltage. The dynamic performance of the proposed system is
simulated in Matlab-Simulink under a nonlinear load consisting of a bridge
rectifier with voltage-fed load.

KEYWORDS:

1.Power
Quality

2.DSTATCOM

3.DVR

4.UPQC

5.Solar PV

6.MPPT

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.
1. System Configuration PV-UPQC

EXPECTED SIMULATION RESULTS:

Fig.
2. Performance PV-UPQC at steady state condition

Fig. 3. PCC Voltage Harmonic Spectrum and THD

Fig. 4. Load Voltage Harmonic Spectrum and THD

Fig. 5. Load Current Harmonic Spectrum and THD

Fig.
6. Grid Current Harmonic Spectrum and THD

Fig.
7. Performance PV-UPQC at varying irradiation condition

Fig. 8. Performance of PV-UPQC under voltage sag and
swell conditions

CONCLUSION:

The dynamic performance of three-phase PV-UPQC has been
analyzed under conditions of variable irradiation and grid voltage sags/swells.
It is observed that PV-UPQC mitigates the harmonics caused by nonlinear and
maintains the THD of grid voltage, load voltage and grid current under limits
of IEEE-519 standard. The system is found to be stable under variation of
irradiation from 1000𝑊/𝑚2
to 600𝑊/𝑚2.
It can be seen that PV-UPQC is a good solution for modern distribution system
by integrating distributed generation with power quality improvement.

Friday, 10 August 2018

Use of power electronic converters with nonlinear
loads leads to power quality problems by producing harmonic currents and
drawing reactive power. A shunt active power filter provides an elegant
solution for reactive power compensation as well as harmonic mitigation leading
to improvement in power quality. However, the shunt active power filter with PI
type of controller is suitable only for a given load. If the load is varied,
the proportional and integral gains are required to be fine tuned for each load
setting. The present study deals with hybrid artificial intelligence controller,
i.e. neuro fuzzy controller for shunt active power filter. The performance of
neuro fuzzy controller over PI controller is examined and tabulated. The
salvation of the problem is extensively verified with various loads and plotted
the worst case out of them for the sustainability of the neuro fuzzy
controller.

KEYWORDS:

1.Active Power Filter

2.Neuro Fuzzy Controller

3.Back Propagation Algorithm

4.Soft Computing

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig 1. Schematic Diagram of Shunt Active
Power Filter

EXPECTED
SIMULATION RESULTS:

Fig
2. (a) Waveform of Load Current, Compensating Current, Source

Current
and Source Voltage for Case V of Table1 (1kVA with α=60o) and

(b)
Waveform of Source Voltage and in phase Source Current of Fig. (a) Reproduced

CONCLUSION:

The
application of hybrid artificial intelligence technique on shunt active power
filter is proved to be an eminent solution for the mitigation of harmonics and
the compensation of reactive power. The hybrid artificial intelligence used
here is the neuro fuzzy controller. It takes the linguistic inputs as a fuzzy
logic controller and it adapts any situation in between the running of the
program as the neural network. The simulation results states that the active power
filter controller with neuro fuzzy controllers have been seen to eminently
minimize harmonics in the source current when the load demands non sinusoidal
current, irrespective of whether the load is fixed or variable when compared to
PI Controller. Simultaneously, the power factor at source also becomes the
unity, if the load demands reactive power. The neuro fuzzy controller is far
superior to the PI controller for all the loads. In the present work, a range
of values of the load is considered to robustly test the controllers. It has
been demonstrated that neuro fuzzy controller offers more acceptable results
over the PI controller. The neuro fuzzy controller, therefore, significantly
improves the performance of a shunt active power filter.

This work
describes artificial neural network (ANN) based control algorithm for three
phase three wire shunt active power filter (SAPF) to compensate harmonics and
improve power quality. System consists of three phase insulated gate bipolar transistors
IGBT based current controlled voltage source inverter (CC-VSI), series coupling
inductor and self supported DC bus. Increasing application of non-linear loads
causes power quality problem. SAPF is one of the possible configurations to
improve power quality. Traditional SAPF have PLL based unit template generator
for extraction of fundamental signal. Traditional PLL needs to be tuned to
obtain optimal performance for frequency estimation. It requires initial
assumptions for fundamental frequency and minimum frequency. With varying
frequency, it can’t be dynamically tuned for optimal performance. A new ANN based
fundamental extraction based on Lavenberg Marquardt back propagation algorithm
is proposed. Proposed SAPF is modeled in Simulink environment. Simulated
results show the capability of proposed system.

KEYWORDS:

1.Shunt Active Power Filter

2.Artificial Neural Networks

3.Indirect Current Control Technique

4.Power Quality

SOFTWARE:
MATLAB/SIMULINK

BLOCK
DIAGRAM:

Fig.1.
Proposed system configuration block with SAPF

EXPECTED SIMULATION RESULTS:

Fig.2.
Source voltages

Fig.3.
Unbalanced load voltages

Fig.4. Unbalanced load currents

Fig.5.
Simulation result for proposed system under non linear with

unbalance
load condition

Fig.6.
DC link voltage

Fig.7. Active power

Fig.8.
Reactive power

Fig.9.
Power factor

Fig.10.
Harmonic spectrum of load current before compensation for three phase SAPF with
non linear load

Fig.12.
Harmonic spectrum of source currents (phase a) after compensation for ANN based
three phase APF with non linear load with unbalance

CONCLUSION:

ANN based phase-locking scheme has been
proposed in this paper to control three phase-three wire shunt APFs. Widrow-Hoff
weights updating algorithm has been incorporated to reduce calculation time in
estimation of harmonic components. To validate effectiveness of proposed approach
for real-time applications, indirect current control theory based controller
has been developed. Design parameters of power circuit and control circuit have
been calculated and robustness of proposed system has been established with Matlab/Simulink.
Simulation result and spectral response show that, obtained source current THDs
is below 5% as prescribed by IEEE-519 standard. Dynamic performance of proposed
approach has been found satisfactory under sudden change in load and frequency.

Use of power electronic converters with nonlinear loads
produces harmonic currents and reactive power. A shunt active power filter
provides an elegant solution to reactive power compensation as well as harmonic
mitigation leading to improvement in power quality. However, the shunt active
power filter with PI type of controller is suitable only for a given load. If the
load is varying, the proportional and integral gains are required to be fine
tuned for each load setting. The present study deals with neural network based
controller for shunt active power filter. The performance of neural network
controller evaluated and compared with PI controller.

KEYWORDS:

1.Active Power Filter

2.Neural Networks

3.Back Propagation Algorithm

4.Soft Computing.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig 1. Schematic Diagram of Shunt Active
Power Filter

EXPECTED SIMULATION RESULTS:

Fig 2. (a)
Waveform of Load Current, Compensating Current, Source Current and Source
Voltage for 1kVA with 􀄮=60º and (b)
Waveform of Source Voltage and in the phase Source Current of Fig. (a)

CONCLUSION:

The
active power filter controller with neural network based controller has been
seen to eminently minimize harmonics in the source current when the load
demands non sinusoidal current, irrespective of whether the load is fixed or
varying. Simultaneously, the power factor at source also becomes the unity, if the
load demands reactive power. Thus, neural network based controller is far
superior to PI type of controller which requires fine tuning of Kp and Ki every
time the load changes. In the present work, the performance of a range of values
of the load is considered to robustly test the controller. It has been
demonstrated that neural network based controller, therefore, significantly
improves the performance of a shunt active power filter.